A former senior manager of the German group Siemens has been given a two-year suspended prison sentence and fined €108,000 (£85,000) for his role in setting up slush funds and shell companies to help his firm win contracts abroad.

Reinhard Siekaczek was found guilty of 49 counts of breach of trust in the first trial arising from a wide-ranging investigation into suspected corruption, which has damaged the reputation of the huge engineering group.

The company has acknowledged that the scandal involves at least €1.3bn of what have been described as unclear payments.

Siekaczek, a 57-year-old former sales manager at Siemens' telecommunications division, had admitted building a system of hidden funds. He told the court that he had later tried to stop systematic bribery but top managers failed to act.

Yesterday the presiding judge, Peter Noll, said Siekaczek channelled money into a series of bogus companies but indicated he believed he was only a cog in the machine. "One can assume that Mr Siekaczcek was part of a system of organised irresponsibility that was implicitly condoned," he said.

Noll was critical of Siemens' organisation and controls, and said the responsibilities of the former head of compliance, Albrecht Schäfer, were too narrowly drawn. "It's as if you were to equip the fire department with a toothbrush cup to extinguish fires," he said.

Schäfer had earlier testified that former top executives had ignored repeated warnings about suspicious payments. The judge said it was not clear whether those executives were involved or who had received the payments.

Siekaczek's trial came after a long inquiry by prosecutors in Munich, one of several investigations around the world into the company's activities. The scandal came to light in November 2006 and has cost the jobs of Heinrich von Pierer, the former chairman, and Klaus Kleinfeld, who took over from him as chief executive. Neither has been charged with any wrongdoing and both deny any involvement. Von Pierer refused to testify in June on the grounds that he could incriminate himself.

Siemens' own investigations and others have widened beyond the telecoms unit to include transport and power divisions.